U.S. patent number 5,845,221 [Application Number 08/675,295] was granted by the patent office on 1998-12-01 for load control system for vehicle.
This patent grant is currently assigned to Yazaki Corporation. Invention is credited to Kiyoshi Hosokawa, Yoshinori Ikuta, Nobuhiro Imaizumi.
United States Patent |
5,845,221 |
Hosokawa , et al. |
December 1, 1998 |
Load control system for vehicle
Abstract
A switch operating unit 10 has operating switches for operating
loads. A load control unit controls the corresponding loads in
accordance with the operation of the operating switches according
to information, which is stored in first storage device, as to the
correlation between the operating switches and the loads. A total
rated capacity computation device computes the total rated capacity
of the loads to be driven under the control of the load control
unit according to information, which is stored in second storage
device, as to the rated capacity of each load. When the total rated
capacity exceeds a predetermined allowable capacity, the load
control unit operates to restrict the driving of the low-priority
loads in the order of analog-controlled loads and on-off controlled
loads according to the information stored in the second storage
device.
Inventors: |
Hosokawa; Kiyoshi (Tokyo,
JP), Ikuta; Yoshinori (Shizuoka, JP),
Imaizumi; Nobuhiro (Shizuoka, JP) |
Assignee: |
Yazaki Corporation (Tokyo,
JP)
|
Family
ID: |
15832151 |
Appl.
No.: |
08/675,295 |
Filed: |
July 1, 1996 |
Foreign Application Priority Data
|
|
|
|
|
Jun 30, 1995 [JP] |
|
|
7-166478 |
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Current U.S.
Class: |
701/36;
307/10.1 |
Current CPC
Class: |
B60R
16/0315 (20130101); H02J 1/14 (20130101); H02J
2310/46 (20200101); Y02T 10/92 (20130101); B60R
2016/0322 (20130101) |
Current International
Class: |
H02J
1/14 (20060101); B60R 16/02 (20060101); B60R
016/02 (); B60L 001/00 () |
Field of
Search: |
;701/36
;307/9.1,10.1,10.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
0193485 |
|
Sep 1986 |
|
EP |
|
5-41096 |
|
Jun 1993 |
|
JP |
|
5-55701 |
|
Jul 1993 |
|
JP |
|
Other References
IE.E Proceedings Section A A I, vol. 129, No. 6, Part E, Nov. 1982,
Old Woking, Surrey, GB, pp. 223-228. XP002015112, Preston et al.:
"Multiprocessor Implementation of the Logic Function of a
Multiplexed Wiring System for Automotives", p. 225, column 1, line
1-p. 226, column 2, line 42; figures 1-5, 8..
|
Primary Examiner: Zanelli; Michael
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak &
Seas, PLLC
Claims
What is claimed is:
1. A load control system for a vehicle comprising:
a switch operating unit having various kinds of operating switches
for operating loads installed in a plurality of parts of said
vehicle;
a load control unit for controlling the loads in accordance with
the operation of the operating switches of said switch operating
unit;
first storage means for storing information as to defining the
correlation between the operating switches of said switch operating
unit and said loads, including
second storage means for storing information as to the rated
capacity of each load and its priority order and
total rated capacity computation means for computing the total
rated capacity of said loads driven under the control of said load
control unit through the operation of said operating switches from
the rated capacity of each load stored in said second storage
means,
wherein when the total rated capacity computed from said total
rated capacity computation means exceeds a predetermined allowable
capacity, said load control unit operates to reduce the driving of
low-priority loads according to the information concerning priority
order stored in said second storage means.
2. A load control system as claimed in claim 1, wherein said loads
include analog-controlled loads and on-off controlled loads and
wherein when the total rated capacity computed from said total
rated capacity computation means exceeds the predetermined
allowable capacity in a case where a low-priority analog-controlled
load and an on-off controlled load exist, the load control unit
operates to reduce the driving of the analog-controlled load before
that of the on-off controlled load is fulfilled according to the
information concerning the priority order stored in said second
storage means.
3. A load control system as claimed in claim 2, wherein said load
control unit operates to reduce the driving of the load by lowering
the duty cycle with respect to the rated capacity of each of said
analog-controlled loads.
4. A load control system as claimed in claim 3, wherein said load
control unit further operates to turn off the driving of said
on-off controlled loads when either the duty cycle with respect to
an output rating of any of said analog-controlled loads is less
than a predetermined amount or the computed total rated capacity
exceeds the predetermined allowable capacity after the load control
unit has reduced the driving of the low priority loads.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to load control systems for
vehicles and more particularly to a load control system for a bus
vehicle. The system functions to energize a number of corresponding
vehicle-borne loads in response to the operation of switches with
volumes and on-off switches.
2. Related Art
Various loads such as lamps and motors are generally arranged in
numerous parts of a vehicle body and operating switches
corresponding to the respective loads are also arranged near the
driver's seat, the loads corresponding to the is switches being
fixedly set. Therefore, optimum design is adoptable so that current
capacity at the time of full-load is allowed.
In the case of electric appliances for use in the body of a bus
vehicle, however, variations of switches and loads may be made
according to user's designation. Consequently, it tends to become
uneconomical in view of cost to build a system of the sort
described above to the aforesaid fixed specification.
There has been proposed a load control system intended for solving
the cost problem as disclosed in, for example, Japanese Utility
Model Laid-Open No. 55701/1993, through the steps of standardizing
the hardware configuration of switch input and load output of the
system, storing data for designating the correlation between the
switch input and the corresponding load output into a memory
according to the specification and controlling loads using the data
stored in the memory so that greater variations of switches and
loads can be dealt with by varying the contents of the memory.
In the proposed system above, the number of load driving outputs
and the current capacity of each output have been fixed. However,
the current capacity of each output has been set rather large in
order to increase freedom against the variations. Notwithstanding,
in the case of specification according to which the entire load at
full current capacity is connected to the entire output, the total
capacity may exceed the allowable current capacity of the system
when the entire switch corresponding to these loads is turned on,
which is normally unthinkable. This is due to the fact that the
system is so designed as to avoid overquality in an attempt to
reduce size and cost in consideration of the duty cycle of the
current capacity of each output.
SUMMARY OF THE INVENTION
In view of the foregoing problems, an object of the present
invention is to provide a load control system for a bus vehicle,
which system is capable of properly dealing with over allowable
current capacity while avoiding overquality to reduce size and
cost.
In order to accomplish the object above according to the present
invention, a load control system for a bus vehicle comprises: a
switch operating unit having various kinds of operating switches
for operating loads installed in a plurality of parts of a bus
vehicle, a load control unit for controlling the loads in according
with the operation of the operating switches of the switch
operating unit, and first storage means for storing information as
to defining the correlation between the operating switches of the
switch operating unit and the loads, including
second storage means for storing information as to the rated
capacity of each load and its priority order and total rated
capacity computation means for computing the total rated capacity
of the loads driven under the control of the load control unit
through the operation of the operating switches from the rated
capacity of each load stored in the second storage means, is
characterized in that when the total rated capacity computed from
the total rated capacity computation means exceeds a predetermined
allowable capacity, the switch operating unit operates to restrict
the driving of the low-priority load according to the information
concerning the priority order stored in the storage means.
The loads include analog-controlled loads and on-off controlled
loads and when the total rated capacity computed from the total
rated capacity computation means exceeds the predetermined
allowable capacity in a case where the low-priority
analog-controlled load and the on-off controlled load exist, the
load control unit operates to restrict the driving of the
analog-controlled load before that of the on-off controlled load is
fulfilled according to the information concerning the priority
order stored in the storage means.
The load control unit operates to restrict the driving of the load
by lowering the duty cycle with respect to the rated capacity of
the analog-controlled load.
With the arrangement above and as shown in FIG. 1, the load control
unit 20a11 controls the corresponding loads in accordance with the
operation of the operating switches of the switch operating unit 10
having the various kinds of switches for operating the loads
30a-30e installed in the plurality of parts of the bus vehicle.
During the control operation, since the information, which is
stored in the first storage means 20c, as to defining the
correlation between the operating switches of the switch operating
unit and the loads is utilized, numerous variations can be dealt
with by altering the contents of the memory through the steps of
standardizing the hardware configuration of the switch input and
the load output and storing data conforming to the specification
which designates the correlation between the switch input and the
load output and the like.
The total rated capacity computation means 20a12 computes the total
rated capacity of the loads to be driven under the control of the
switch operating unit through the operation of the operating
switches from the rated capacity of each load stored in the second
storage means 20c2 and when the total rated capacity thus computed
exceeds the predetermined allowable capacity, the load control unit
operates to restrict the driving of the low-priority load according
to the information concerning the priority order stored in the
second storage means. In the case of the specification according to
which the loads at full current capacity are connected to the
entire output, the total rated current capacity never exceeds the
allowable capacity even when all the switches corresponding to the
loads are totally turned on.
The loads include the analog-controlled loads and the is on-off
controlled loads and when the total rated capacity computed from
the total rated capacity computation means exceeds the
predetermined allowable capacity in a case where the low-priority
analog-controlled load and the on-off controlled load exist, -the
load control unit operates to restrict the driving of the
analog-controlled load before that of the on-off controlled load is
fulfilled according to the information concerning the priority
order stored in the storage means. Since load control unit operates
to restrict the driving of the load by lowering the duty cycle with
respect to the rated capacity of the analog-controlled load, the
problem of letting the total rated capacity exceed the allowable
capacity is made solvable without completely turning off any
load.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is diagram illustrating a basic configuration of a load
control system for a bus vehicle according to the present
invention.
FIG. 2 is a diagram illustrating a load control system for a bus
vehicle embodying the present invention.
FIG. 3 is an exemplary arrangement of the control unit of FIG.
2.
FIG. 4 is a data structure to be stored in the data storage unit of
FIG. 2.
FIG. 5 is an exemplary arrangement of the driving unit of FIG.
2.
FIG. 6 is a flowchart showing a process to be performed by CPU of
FIG. 3 according to a predetermined program.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention will subsequently be
described by reference to the accompanying drawings. FIG. 2 is a
circuit diagram illustrating a load control system for a bus
vehicle embodying the present invention. In FIG. 2, reference
numeral 10 denotes a switch operating unit; and 20, a load control
unit for controlling loads 30a-30e on receiving switching signals
from the switch operating unit 10. The switch operating unit 10 has
on-off switches 10a1, 10a2 and switches with volumes 10b1-10b3.
As shown in FIG. 3, the load control unit 20 is provided with a
one-chip microcomputer as a control unit 20a incorporating a
central processing unit (CPU) 20a1 which operates in accordance
with a predetermined control program, a ROM 20a2 for storing
various fixed data in addition to the control program, and a RAM
20a3 having a data area for storing various variable data and a
work area for use during the operation.
The load control unit 20 also has an input interface (I/F) 20b for
inputting switching signals from the switch operating unit 10 to
the control unit 20a, an output interface (I/F) 20c for outputting
control signals from the control unit 20a, a driving unit 20d for
driving loads 30a-30e by controlling supply voltage from a battery
mounted in the bus vehicle via a fusible link FL having a
predetermined capacity in response to the control signal which is
output via the output interface (I/F) 20c, and a data storage unit
20e with a memory for storing data indicative of the correlation
between the switch in the switch operating unit 10 and the
corresponding load and so forth. Further, 20f denotes a power
supply for supplying constant voltage from the battery via the
fusible link FL to each part within the load control unit 20.
The control unit 20a sends the control signal to the corresponding
load in response to the switching signal received from the switch
operating unit 10a and when the control signal is output, the
control unit 20a refers to the data indicating the correlation
between the switches of the switch operating unit 10 in the data
storage unit 20e and the corresponding load. The data storage unit
20e is formed with a memory such as an electrically rewritable
E.sub.2 PROM which is capable of holding data without a backup
power supply. A description will be given of the data to be stored
in the memory by reference to a memory map of FIG. 4.
A load output is designated by a memory address in the E.sub.2
PROM. Information concerning a switch position for designating a
switch in the switch operating unit 10a for operating a load to be
connected to the load output designated by the address is stored in
high-order bits B7-B5 at that address. The information indicating
the correlation between the switch and the load is obtainable from
the information on the switch position represented by B7-B5 and the
address. Moreover, the rated capacity of the load connected to the
load output designated by the memory address is stored in the four
bits of B4-B1 at that address. The rated capacity in the range of
0-15A is set by the four bits. The total rated capacity of the load
connected to the system can be made known by adding up the rated
capacities of the loads connected to the load output. Then the load
driving priority order is stored in B0 of the least significant bit
1. The priority is set to [1] in the case of a load to which a
power saving (restriction on the power supply) is applied and to
[0] in the case of no power saving.
As shown in FIG. 5, the driving unit 20d is arranged as, for
example, a general-purpose load driving circuit and has IPSs
(Intelligent Power Switches) 20d1-20d5 as load output means to
which loads 30a-30e are connected, respectively. The control signal
that the control unit 20a outputs is input to each IPS via the
output interface (I/F) 20c, so that the IPS is turned on/off. In
other words, the IPSs function as those which cause the loads
30a-30c respectively connected thereto to be driven and which
automatically cut off the circuit on detecting overcurrent flowing
as a result of a short in each load. Therefore, a fuse for each
load can be dispensed with. Other switching means with control
inputs such as relays or transistors may be used to constitute the
driving unit 20d.
According to this embodiment of the invention, it is predetermined
that on-off controlled loads are connected to the ISPs 20d1-20d2
out of 20d1-20d5, whereas loads to be controlled in an analog form,
for example, lighting equipment capable of light modulation are
connected to 20d3-20d5.
However, the kind and rated capacity of loads to be connected to
the ISPs 20d1-20d5 would greatly vary with customers'
specifications. The analog control according to this embodiment of
the invention is arranged so that it is effected by making the
on-off duty of the IPSs 20d1-20d5 variable.
Although the maximum rated capacities of loads that can be
connected to the IPSs 20d1-20d5 are predetermined like, for
example, 5A, 5A, 10A, 5A, 5A, a value 30A resulting from adding up
these maximum rated capacities is to be set greater than the
capacity value, for example, 20A of the fusible link FL. For this
reason, the total rated capacity may exceed the allowable capacity
of the system determined by the capacity value 20A of the fusible
link FL, for example, depending on the specification when all the
operating switches are turned on so that the entire load is brought
to the functional state. In such a case as this, the power of the
loads having low priority is saved by making use of the priority
order set to each load so as to decrease the total rated capacity
of the loads in operation up to the allowable capacity range.
According to this embodiment of the invention, the loads to which
the power-saving has been applied may exist in both domains of the
on-off controlled loads and those to be controlled in the analog
form because one bit is used only to set the application or
non-application of the power-saving with respect to the priority
order as stated above according to the aforementioned embodiment of
the invention. In this case, the loads to be controlled in the
analog form are subjected to the power-saving first. At this time,
any load involved is not turned off immediately but reduced to, for
example, 50% in terms of the duty cycle with respect to the output
rating of the load. In a case where the power-saving is
insufficient or where the duty cycle with respect to the output
rating of the load involved is in less than 50% from the beginning,
any other on-off controlled load with the power-saving is also
turned off.
Further, a detailed description will subsequently be given of three
specifications taken by way of example by reference to a table 1
below.
TABLE 1
__________________________________________________________________________
System Connected At the time configuration load Load Duty cycle of
power- Load capacity operating to rating saving output Kind of load
Rating Spec. 1 Spec. 2 Spec. 3 priority Spec. 1 Spec. 2 Spec. 3
Spec. 2 Spec. 3
__________________________________________________________________________
IPS20d.sub.1 Analog 5 A 2 A 5 A 5 A A 40% 100% 100% 100% 100%
IPS20d.sub.2 Analog 5 A 3 A 5 A 5 A A 60% 100% 100% 100% 100%
IPS20d.sub.3 Analog 10 A 5 A 8 A 5 A B 50% 80% 50% 50% 50%
IPS20d.sub.4 On-off 5 A 2 A 2 A 5 A A 40% 40% 100% 40% 100%
IPS20d.sub.5 On-off 5 A 3 A 3 A 3 A B 60% 60% 60% 60% 0% Total 30 A
15 A 23 A 23 A 75% 115% 115% 20 A 20 A Allowable 20 A Over Over
capacity
__________________________________________________________________________
A: Priority is high B: Priority is low
In the case of the specification 1, first, the rated capacities of
loads connectable to IPSE 20d1-20d5 are each 2A, 3A, 5A, 2A and 3A,
which are each lower than the maximum rated capacities of the IPSs
20d1-20d5: 5A, 5A, 10A, 5A and 5A. The duty cycles with respect to
the ratings are each 40%, 60%, 50%, 40% and 60%, whereas its total
rated capacity 15A is less than the allowable capacity 20A.
Therefore, the power is not saved despite the leveled-down priority
of the IPSs 20d3 and 20d5 to which the analog-controlled load and
the on-off controlled load are connected, respectively.
In the case of the specification 2, further, the rated capacities
of loads connectable to IPSs 20d1-20d5 are each 5A, 5A, 8A, 2A and
3A, which are, needless to say, each lower than the maximum rated
capacities of the IPSs 20d1-20d5. In addition, the duty cycles with
respect to the ratings are each 100%, 100%, 80%, 40% and 60%,
whereby its total rated capacity 23A exceeds the allowable capacity
20A (the duty cycle 115% with respect to the allowable capacity).
Therefore, the power needs saving when the entire load is turned on
and the duty cycle with respect to the rating of the
analog-controlled load connected to the low-priority IPSE 20d3 is
first reduced from 80% to 50%. As a result of the power-saving, the
total rated capacity is leveled down to 20A as the allowable
capacity even when the entire load is turned on.
In the case of the specification 3, finally, the rated capacities
of loads connectable to IPSs 20d1-20d5 are each 5A, 5A, 5A, 5A and
3A, whereas the duty cycles with respect to the ratings are each
100%, 100%, 50%, 100% and 60%, whereby its total rated capacity 23A
exceeds the allowable capacity 20A (the duty cycle 115% with
respect to the allowable capacity). Therefore, the power needs
saving when the entire load is turned on but since the duty cycle
with respect to the rating of the analog-controlled load connected
to the low-priority IPS 20d3 has already been brought to 50%, the
on-off controlled load connected to the low-priority IPS 20d5 is
turned off likewise in this case. As a result of the power-saving,
the total rated capacity is leveled down to 20A as the allowable
capacity even when the entire load is turned on.
A detailed description will subsequently be given of the operation
as roughly described above by reference to a flowchart of FIG. 6 in
which a process is performed by the CPU 20a1 of the microcomputer
constituting the control unit 20a according to a predetermined
program.
The CPU 20a1 starts operating when the power supply is put to work,
carries out initialization at an initial Step S1, reads the data
stored in the data storage unit 20e as shown in FIG. 4 and stores
the data in the predetermined area of a RAM 20a3. Then Step S3 is
followed wherein the total rated capacity of the entire connected
load on the basis of the data stored in the RAM 20a3 is computed.
Subsequently, Step S4 is followed wherein the total rated capacity
computed at Step S3 above is compared with the allowable capacity
of the system predetermined in the data area of, for example, a ROM
20a2, so that it is decided whether the total rated capacity
becomes greater than the allowable capacity.
When the decision made at Step S4 is YES, that is, when the total
rated capacity is greater than the allowable capacity, Step S5 is
followed and priority order is checked by means of the data stored
in the RAM 20a3 at Step S2. Then Step S7 is followed after the load
intended for power-saving is set at Step S6 depending on the
checked result. When the decision made at Step S4 is NO, Step S7 is
directly followed by skipping Step S4 and Step S5.
At Step S7, signals for operating the respective switches of the
switch operating unit 10 are input and then Step SB is followed so
as to make a decision on whether all the switches are in the ON
state. When the decision made at Step 58 is YES, Step S9 is
followed and the power-saving process is performed. At the time the
power-saving process is performed at Step S9, the load set as a
power-saving object at Step S6 is subjected to the power-saving and
then Step S10 is followed to perform the outputting process. In
case where the decision made at Step S8 is NO, Step S10 is followed
by skipping Step S9 to perform the outputting process. After Step
S10, Step S7 is followed again to repeat the operations above.
As is obvious from the operations described above, the CPU 20a1
acts as not only a load control unit 20a11 for controlling the
corresponding loads 30a-30e in accordance with the operation of the
operating switches of the switch operating unit 10 but also a total
rated capacity computation means 20a12 for computing the total
rated capacity of the loads to be driven under the control of the
load control unit through the operation of the operation switches
from the rated capacity of each load stored in the data storage
unit 20e.
When the total rated capacity computed by the total rated capacity
computation means 20a12 exceeds the predetermined allowable
capacity, the load control unit 20a11 operates to restrict the
driving of the low-priority load according to the information
concerning the priority order stored in the data storage unit
20e.
Further, in a case where the low-priority analog-controlled load
and the on-off controlled load exist, the load control unit 20a11
operates to restrict the driving of the analog-controlled load
before that of the on-off controlled load is fulfilled according to
the information concerning the priority order stored in the data
storage unit 20e when the total rated capacity computed by the
total rated capacity computation means 20a12 exceeds the
predetermined allowable capacity likewise.
Further, by lowering the duty cycle with respect to the rated
capacity of the analog-controlled load, the load control unit 20a11
also operates to restrict the driving of the load.
In these embodiments, although a specific description is not
included, CPU 20a.sub.1 receives an amount of operating volume of
the switches with volume through analog-digital conversion and
controls driving of the analog-controlled load on the basis of the
amount of operating volume of the switches with volume.
Although control has been exerted so that the utilization factor of
the load output remains at 50% at the time of power-saving for
restricting the driving of the analog-controlled load according to
the aforementioned embodiment of the invention, it may also be
exerted to set the factor at 50% of the rated capacity of the
load.
As set forth above, since the information as to defining the
correlation between the operating switch of the switch operating
unit and the load is utilized, numerous variations can be dealt
with by varying the contents of the memory through the steps of
standardizing the hardware configuration of the switch input and
the load output and storing data conforming to the designated
specification such as the correlation between the switch input and
the load output.
Further, the current capacity of each output has been set rather
large in order to increase freedom against the variations,
whereupon the total capacity exceeds the allowable capacity when
the switches corresponding to the respective loads are totally
turned on in the case of specification according to which the
entire load at full current capacity is connected to the entire
output. However, the total rated capacity of the loads to be driven
under control is computed from the rated capacity of the respective
loads and when the total rated capacity exceeds the predetermined
allowable capacity, the driving of the low-priority load is
restricted according to the information concerning the priority
order thus stored, whereby the total rated capacity is prevented
from exceeding the allowable capacity. Consequently, it is possible
to reduce the size and cost of the load control system as
overquality is avoided.
When the total rated capacity exceeds the predetermined allowable
capacity, the driving of the analog-controlled load is restricted
before that of the on-off controlled load is fulfilled and by
lowering the duty cycle with respect to the rated capacity of the
analog-controlled load in particular, the driving of the load is
restricted. Therefore, the problem of letting the total rated
capacity exceed the allowable capacity is made solvable without
completely turning off any load.
* * * * *